The primary objective of this proposal is to determine the propensity of silicone-gel to induce an auto-immune syndrome in an animal model system. To this end we have proposed a three step approach: 1. animal testing to determine the relative risk of silicone-gel/oil of inducing an auto-immune syndrome. 2. In-vitro testing of silicone-gel/oil capacity to activate macrophages. 3. Physicochemical testing of the silicone-gel/oil. Steps 2 and 3 will aid in our understanding of the adjuvant properties of silicones and a better understanding of adjuvancy in general and lead to the development of safer biological implants. The health relatedness of these studies will aid in determining the risk of developing an auto- immune ailment in women who have received silicone-gel filled mammary implants.